Alkoxylated alkylamines/alkyl ether amines with peaked distribution

ABSTRACT

The present invention generally relates to a process for preparing the alkoxylated alkylamines and/or alkyl ether amines. The process consists of three stages, and utilizes an alkali catalyst. The alkoxylated alkyl amines and alkoxylated alkyl ether amines prepared by the process possess the peaked distribution and contain less hazardous by-product.

REFERENCE TO RELATED APPLICATIONS

This application is a Divisional application of U.S. Ser. No.11/575,847, filed Mar. 22, 2007, which is a U.S. National Stageapplication of International Patent Application No. PCT/US2005/034186,filed Sep. 23, 2005, which claims the benefit of U.S. Ser. No.60/637,172, filed Dec. 17, 2004, and U.S. Ser. No. 60/612,597, filedSep. 23, 2004, the entire disclosures of which are all incorporatedherein by reference.

The claimed invention was made by or on behalf of Monsanto Company andAkzo Nobel, parties to a joint research agreement in effect before thedate of the claimed invention, and as a result of activities within thescope of the joint research agreement.

FIELD OF THE INVENTION

The present invention relates to an alkali-catalyzed process forpreparation of alkoxylated alkyl amines or alkoxylated alkyl etheramines with peaked distribution.

BACKGROUND OF THE INVENTION

Alkoxylated alkyl amines and alkyl ether amines, particularlyethoxylated alkyl amines and ethoxylated alkyl ether amines, have manyapplications in industry. They can be usefully employed as adjuvants inpesticide formulations, textile processing aids, dye transferinhibitors, acid thickeners, detergent boosters, degreasers, anti-staticagents and the like.

Alkoxylated alkyl amines and alkoxylated alkyl ether amines arematerials possessing the following general structures (I), respectively:

In conventional alkoxylated alkylamines, R is typically selected from alinear or branched, saturated or non-saturated alkyl group containing8-22 carbon atoms. In alkoxylated etheramines, R corresponds to theformula:

R¹—O-(A)_(a)-(B)_(b)-(C)_(c),

where R¹ is typically a linear or branched, saturated or non-saturatedalkyl group containing 8-22 carbon atoms, A and B are alkylene oxidegroups containing 2-4 carbon atoms, C is alkylene group containing 3-4carbon atoms, a, b each vary from 0-5, c is 1, X, Y, Z are alkyleneoxide groups containing 2-4 carbon atoms, x is 1, and y and z eachindependently vary from 0-15.

As illustrated by general formula (I), the alkoxylated alkylamines/alkoxylated alkyl ether amines possess a surfactant structurewhich is composed of the lipophilic groups (R or R¹) and the hydrophilicgroups (polyalkylene oxide). In their designed applications, theperformance of alkoxylated alkyl amines and alkoxylated alkyl etheramines is dependent on a balance between the lipholicity and thehydrophilicity provided by these groups.

Even when the lipophilicity-hydrophilicity balance does exist, theperformance of the alkoxylated alkyl amines/alkoxylated alkyl etheramines is not necessarily optimal. Traditionally, these materials areprepared from the base-catalyzed alkoxylation of the corresponding alkylamines/alkyl ether amines. Such an alkoxylation reaction is actually thepolymerization reaction of alkylene oxide that includes thecharacteristic propagation and chain transfer steps of thepolymerization process. For this reason, the resulting alkoxylatedalkylamine/alkyl ether amine is not a pure compound, but a mixture ofmany homologs.

As an example, FIG. 1 illustrates the homolog distribution ofethoxylated tallow amine prepared from the regular hydroxide-catalyzedethoxylation of tallow amine with 5 moles of ethylene oxide. As shown inFIG. 1, the resulting ethoxylated product is not a single compoundcontaining 5 (CH₂CH₂O) units as the general structure (structure I, with2x+2y+2z=5) may suggest. Instead, the product is a mixture of severalhomologs whose total ethylene oxide units varies from 2 to 10. Amongthese homologs, only those in the middle of the distribution range havethe proper liphophilic-hydrophilic balance for certain applications and,therefore, are generally preferred. For example, in the case of anethoxylated product comprising an average ratio of 5 alkylene oxideunits per molecule, homologs having a desired lipophilic-hydrophilicbalance typically range from 3EO to 5EO where “EO” is an ethylene oxideunit. Homologs with shorter EO chain length (<3EO) or longer EO chainlength (>5EO) are not desirable for the applications for which a 5EO/amine ratio surfactant is ordinarily prescribed, since such longerand shorter homologs are either too lipophilic or too hydrophilic forthe applications utilizing this product. For at least some applications,the presence of especially long species is particularly disadvantageous,e.g., species having an EO/amine ratio of more than about 1.5× thetarget ratio. Therefore, it is advantageous to develop an alkoxylationprocess that results in alkoxylated products with peaked distribution.

Accordingly, it is an object of the present invention to develop aprocess for preparation of alkoxylated ethoxylated alkyl amines andalkyl ether amines, particularly ethoxylated alkylamine and ethoxylatedalkyl ether amine with peaked distribution having greatly minimizeddrawbacks compared to those associated with the acid-catalyzed process.

U.S. Pat. No. 4,483,941 describes the preparation of ethoxylated organicmaterials comprising a peaked distribution of homologs, as prepared byethoxylation in the presence of BF₃ and metal alkyls or metal alkoxides,SiF₄ and metal alkyls or metal alkoxides, or mixtures of all thesecatalysts. The reference lists alcohols, alkyl phenols, polyols,aldehydes, ketones, amines, amides, organic acids and mercaptans assubstrates that may be ethoxylated. The patent includes a long list ofamines that are subject to ethoxylation, particularly includingoctylamine and hexadecylamine. Working examples describe ethoxylation ofO₁₂ to O₁₄ alcohols.

East German patent DD 219,478 describes the ethoxylation of amines inthe presence of Lewis acid catalysts. A number of working examples areincluded which embody reactions with C₁₂ primary amine at ethylene oxideto amine ratios in the ranges of about 2, 3 and 6. At ratios of about 3and about 6, final reaction temperatures range from 179° to 207° C.

U.S. Pat. No. 6,376,721 describes the alkoxylation of alcohols, amines,mercaptans and amides in the presence of a rare earth triflimidecatalyst to obtain a peaked distribution of homologs. Working examplesdescribe the ethoxylation of dodecanol.

Hreczuch & Szymanowski, Recent Res. In Oil Chem., 2 (1998), pp. 63-76describes ethoxylation in the presence of a calcium-based W7™ catalystto obtain narrow range distributed ethoxylated alcohols. FIG. 6 of thisreference also reflects the ethoxylation of tallowamine in the presenceof this catalyst and provides a curve illustrating distribution ofhomologs. The reference explains that in conventional ethoxylation of analcohol, the reaction rate constants increase for successive stages ofoxyethylene, which results in a wide distribution of homologs andtypically a significant fraction of unreacted alcohol. It is furtherexplained that the kinetics of alkylamine ethoxylation are differentfrom the kinetics of alcohol ethoxylation.

WO 02/38269 describes a catalyst comprising Ca sulfate, Ca acetate, lowmolecular weight Ca alcoholate and a crystalline phase in the form oforganic Ca and sulfur compounds as a catalyst in the ethoxylation ofalcohols to obtain a narrow distribution of homologs, and the use ofsuch catalyst in the ethoxylation of organic substrates.

For a number of important commercial and industrial applications, it isdesirable to provide alkoxylated alkyl(ether) amines that impartimproved functional properties to formulations in which they areincorporated.

Among the particular applications in which alkoxylated alkylamine andalkoxylated etheramine surfactants have been used is herbicidalformulations, such as aqueous liquid glyphosate formulations comprisinga salt of glyphosate, wherein they may serve to increase the efficacy ofthe herbicide in controlling or destroying unwanted vegetation.

N-phosphonomethylglycine, otherwise known as glyphosate, is well knownin the art as an effective post-emergent foliar applied herbicide.Glyphosate is an organic compound that at neutral PH, contains threeacidic protonatable groups, and in its acid form is relatively insolublein water. Glyphosate is, therefore, normally formulated and applied as awater-soluble salt. Although monobasic, dibasic and tribasic salts ofglyphosate can be made, it has generally been preferred to formulate andapply glyphosate, in the form of a monobasic salt, for example as amono-(organic ammonium) salt such as the mono (isopropylamine), oftenabbreviated to IPA, salt, or as either monobasic or dibasic ammoniumsalt.

When the terms “ammonium”, “monoammonium” and “diammonium” are usedherein to refer to salts of glyphosate, these terms apply strictly toinorganic ammonium, i.e., NH₄ ⁺, unless the context demands otherwise.Glyphosate rates and concentrations given herein, even where theglyphosate is present as a salt or salts, are expressed as acidequivalent (a.e.) unless the context demands otherwise.

For many applications, glyphosate salts generally require the presenceof a suitable surfactant for best herbicidal performance. The surfactantmay be provided in the concentrate formulation, or it may be added bythe end user to the diluted spray solution. The choice of surfactant canbe very important since there are wide variations among surfactants intheir ability to enhance the herbicidal efficacy of glyphosate forparticular applications.

Use of a highly concentrated aqueous formulation of glyphosate in theform of a salt made with the inorganic base ammonia and potassium isadvantageous. Ammonia and potassium are low in cost, readily available,low in molecular weight, relatively soluble in water. Additionally, theyare natural nutrients for the growth of plants and other organisms. Bothpotassium salts and ammonium salts have been used in substantialcommercial volumes. Not all surfactants are as compatible with thepotassium and ammonium salts at higher concentrations as they typicallyare with the isopropylamine salt, especially in concentrated aqueousliquid formulations. The use of ammonium salts of glyphosate forpreparing aqueous concentrate formulations of glyphosate suitable forkilling and controlling weeds and other plants has, however, beensomewhat limited due to difficulties arising from chemical and physicalproperties thereof, lack of suitable surfactants for preparinghigh-loaded liquid concentrates of such salts, reduced weed control, andrequirement for complex processes for preparing liquid ammoniumglyphosate compositions.

Potassium salts have recently been introduced to the market and havebeen highly successful. However, potassium salts are not as easy toformulate as isopropylamine salts, for example. With respect tostability, especially as reflected in the cloud points of high loadconcentrates, the constraints on selection and concentration ofsurfactants in high load potassium salt solutions are generally morelimiting than in the case of isopropylamine salts.

The economical preparation of high efficacy glyphosate salt solutionsdepends on selecting a suitable surfactant or combination ofsurfactants, and providing an optimal concentration of thesurfactant(s), often the highest concentration(s) that can be achievedwithout sacrifice of stability. Ethoxylated alkylamines have provenexcellent bioefficacy in enhancing the herbicidal potency of glyphosate.However, in a concentrated glyphosate formulation with sufficientloading of the useful ethoxylated alkylamines, especially in potassiumand ammonium glyphosate formulations, the formulation may not be stableat elevated temperature. Above a threshold glyphosate concentration, anysubstantial increase in the concentration of surfactant is typicallyonly achievable at the expense of reducing glyphosate a.e. loading(concentration of glyphosate active). Likewise, any substantial increasein glyphosate a.e. loading of these products is often achievable only atthe expense of surfactant concentration and may therefore impose aconstraint on formulating to a surfactant concentration that is optimalfor a desired application. Generally, it is desirable to develop anstable aqueous ammonium, potassium, or mixed salts glyphosateformulation (i) having high glyphosate a.e. loading, (ii) containing anethoxylated alkylamine surfactant, and (iii) having a high enoughconcentration of that surfactant to provide formulation stability andefficacy sufficient for the application for which a given formulation isprepared. There is a constant objective of providing formulations ofimproved herbicidal efficacy, improved storage and handlingcharacteristics, or reduced cost, or which meet two or more of suchcriteria.

In this context, a C₈ to C₂₂ alkylamine substituted by reaction with twomoles of alkylene oxide, i.e., a bis(hydroxyalkyl)amine has a highdegree of compatibility with a glyphosate salt, but limited value as anadjuvant to enhance the efficacy of the herbicide. C₈ to O₂₂ alkylamineshaving longer chain alkylene oxide substituents are more effective asadjuvants but are not as compatible with concentrated aqueous solutionsof glyphosate salts, and may cause the formulation to suffer from arelatively low cloud point, e.g., <35° C. For certain herbicidalapplications, the optimal surfactant may typically have an averagealkylene oxide to amine ratio between about 3 and about 6. But evenwhere the surfactant possesses such an average ratio, it may containsome unavoidable fractions of <3:1 (EO to amine ratio) and >6:1 species,the presence of which can detract from either performance properties orstability of the formulation. In this case, species having a ratioof >8:1 may have a particularly adverse effect on stability. However,there are other applications where glyphosate formulations may typicallyinclude a surfactant wherein the average alkylene oxide to amine ratiois in the range of about 8 to about 12, or about 12 to about 18. Aqueousliquid concentrates comprising the latter surfactants are formulated ina manner which preserves stability despite the relatively long alkyleneoxide chains, but it remains preferable to minimize the concentration ofhomolog species that are well above the target, e.g., in the case of asurfactant designed to have a ratio between 8 and 12, it may bepreferable to minimize the fraction of homologs having an alkyleneoxide/amine ratio>12:1, or in the case of a surfactant designed to havea ratio between 12 and 18, it may be preferable to minimize the fractionwherein the ratio is greater than about 20:1 or 22:1.

SUMMARY OF THE INVENTION

The present invention generally relates to an alkoxylation process forthe preparation of alkoxylated alkyl amines/alkoxylated alkyl etheramines with peaked distribution, to the products prepared therefrom andapplications of same. Specific processes are described for thepreparation of ethoxylated alkylamines including a Lewis acid catalyzedprocess and a process of the present invention while promoting thepeaked distribution of the ethoxylated products.

The present invention particularly relates to ethoxylated alkylaminesand alkyletheramines that exhibit favorable compatibility withglyphosate and to glyphosate formulations comprising same. The specificethoxylated alkylamines and alkyletheramines of the invention possess arelatively high concentration of the mid-range homologs that enablesthem to be compatible with glyphosate herbicide actives while retainingtheir characteristic adjuvancy. The ethoxylated alkylamines of theinvention may further be useful in the preparation of glyphosateformulations of enhanced compatibility as compared to similarformulations which incorporate alkoxylated alkylamines of the prior arthaving a relatively flat or wide distribution of homologs.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1: Homolog distribution of tallow amine prepared with 5 moles ofethylene oxide by the regular hydroxide-catalyzed process.

FIG. 2: Homolog distribution of ethoxylated coco amine prepared with 5moles of ethylene oxide by the “R” process (C/15) and “S”process(C/15S).

FIG. 3: Homolog distribution of ethoxylated cocoamine prepared with atotal of 6 moles of ethylene oxide by the “R” process (C/16) and the “S”process (C/16S).

FIG. 4: Homolog distribution of the 6-mole EO adduct of coco amineprepared by the regular ethoxylation process (6RP) and the newethoxylation process (6NP). The degree of peaking is 60 for 6NP and 49for 6RP.

FIG. 5: Homolog distribution of 8-mole EO adduct of coco amine preparedby the regular ethoxylation process (8RP) and the new ethoxylationprocess (8NP). The degree of peaking is 51 for 8NP and 42 for 8RP.

FIG. 6: Homolog distribution of 9-mole EO adduct of coco amine preparedby regular ethoxylation process (9RP) and new ethoxylation process(9NP). The degree of peaking is 50 for 9NP and 43 for 9RP.

FIG. 7: Homolog distribution of 9-mole EO adduct of tallowamine preparedby regular ethoxylation process (9R) and new “N” ethoxylation process(9N). The degree of peaking is 53 for T/19N and 43 for T/19R.

DETAILED DESCRIPTION OF THE INVENTION

Alkoxylated alkyl amines and ethoxylated alkyl ether amines of theinvention are materials possessing the following general structure (I):

wherein R is selected from a linear or branched, saturated ornon-saturated alkyl group containing 8-22 carbon atoms or a group of theformula

R¹—O-(A)_(a)-(B)_(b)-(C)_(c),

where R¹ is selected from a linear or branched, saturated ornon-saturated alkyl group containing 8-22 carbon atoms, A and B arealkylene oxide groups containing 2-4 carbon atoms, C is alkylene groupcontaining 2-4 carbon atoms, a, b each vary from 0-5, c is 1, X, Y, Zare alkylene oxide groups containing 2-4 carbon atoms, x is 1, and y,y′, z and z′ each independently vary from 0-15.

By utilizing the terminology “alkoxylated alkyl(ether)amine”, it is tobe understood herein that the present inventors intend either or both ofalkoxylated alkyl amines and alkoxylated alkyl ether amines. Thealkoxylated alkyl amine/alkyl ether amine compositions of the inventionare not single compounds as suggested by their general structure (I),but rather, they comprise a mixture of several homologs having variedpolyalkylene oxide chain length. Among the homologs, only those with thenumber of total alkylene oxide units per mole of amine closer to themost prevalent alkylene oxide adduct are preferred; homologs whosenumber of total alkylene oxide units is much lower or much higher thanthe most prevalent alkylene oxide adduct are undesirable since they aretoo liphophilic or too hydrophilic to be suitable for the applicationfor which the alkoxylated alkylamine/alkyl ether amine are designed. Incertain applications, for example, as surfactants in certain herbicidalformulations, the homologs having alkylene oxide chains significantlylonger than average are particularly disadvantageous with respect tostability.

Alkoxylated alkyl amines and alkoxylated alkyl ether amine are preparedfrom the reaction of the corresponding primary alkyl amine/alkyl etheramine with a selected number of moles of alkylene oxide. Usingethoxylated alkylamines (V) as an example, the prior art generallydescribes the synthesis of ethoxylated alkyl amines in a two-stageprocess:

-   -   1) Reaction of two moles of ethylene oxide with the primary        alkylamine (II) to yield the intermediate (III)        (N,N-bis-(2-hydroxyethyl)N-alkylamine). No catalyst is required        for this reaction.

-   -   2) Reaction of additional moles of ethylene oxide with the        intermediate (III) to yield the desired final ethoxylated        alkylamine product (V) not having a peaked distribution. This        reaction requires the use of a catalyst.

Based on the type of catalysts, there are two types of ethoxylationprocesses described in the prior art. In the regular ethoxylationprocess commonly used in industry, the catalyst is a base, preferably ahydroxide such as sodium hydroxide or potassium hydroxide. We denotethis as the “R” process. With this catalyst, the rate of theethoxylation reaction is fast, and the formation of by-products, e.g.,oxygenated hydrocarbons such as dioxane, and various (poly)ethyleneglycol derivatives (EGDs), is minimal. However, the catalyzedethoxylation in the second stage follows a polymerization mechanism thatincludes its characteristic propagation and chain transfer steps. As aresult, the ethoxylated product obtained does not have a peakeddistribution of total ethylene oxide substitution and possesses higherconcentration of the undesired (too lipophilic/too hydrophilic)homologs.

As recounted above, the prior art also describes another ethoxylationprocess designed to obtain a preferred peaked distribution ofalkoxylated alcohols, aldehydes, ketones, or alkylamines. We denote thisas the “S” process. In this process, the ethoxylation is catalyzed by aLewis acid, preferably Boron Trifluouide, and follows a differentmechanism. The resulting ethoxylated product possesses a peakeddistribution, with highest concentration is of the homologs generally inthe middle of the distribution range, or in any event more concentratedin a desired region than the homologs of an alkoxylated alkylamine.Because the concentration of the undesired homologs is lower in thiscase, the performance of the ethoxylated alkylamine/alkyl ether amine inthe applications they are designed for is optimized. Still otherprocesses for producing peaked distribution alkoxylated organiccompounds use calcium or rare earth based catalysts.

However, so far as is known, neither peaked distribution alkoxylatedalkylamines nor peaked distribution alkoxylated etheramines have beencommercially available, and the use of alkoxylated alkylamines oretheramines has not been described in applications such as herbicidalformulations, or, more particularly, herbicidal formulations comprisingglyphosate salts. One of the objects of the present invention is tocover the glyphosate formulations with any alkylamines and etheramineswith peaked EO distribution.

Generally, the peaked distribution alkoxylated alkylamines andetheramines of the present invention can be prepared by any processwhich provides the favorable distribution and/or favorable propertiesdescribed herein.

Preferably, alkoxylation is conducted according to one or the other oftwo novel processes.

One process, the “S” process, utilizes a Lewis acid catalyst of the typetaught by the prior art, but under conditions which differ from thoseemployed in known prior art processes for alkoxylation of alkylamines.The other and generally preferred process, which we denote as the “N”process, optionally uses an alkaline catalyst of the type used in theconventional (“regular”) process for the commercial manufacture ofalkoxylated alkylamines, but proceeds under a set of conditions whichnonetheless affords a peaked distribution by comparison to thecommercially available surfactants.

According to the “S” process, an alkylamine or etheramine is reactedwith an alkylene oxide in the presence of a Lewis acid catalyst,preferably boron trifluoride, within a preferred temperature range. Ithas been discovered that the ethoxylated alkylamines andalkyletheramines prepared from such a process exhibit improvedcompatibility with glyphosate while retaining their characteristicadjuvancy. Alternative catalyst systems promoting the peakeddistribution can also be employed, and it is believe that the productsprepared from the ethoxylation utilizing these alternative catalystsystems may also be useful in the context of the present invention. Anexample of such a system can be found in, for example, U.S. Pat. No.6,376,721 which utilizes a rare earth triflimide catalyst.

The typical “S” ethoxylation process according to the invention alsoinvolves two stages. In Stage 1, the formation of the intermediate (V)(N,N-bis(2-hydroxyethyl)-N-alkylamine or etheramine), is the same asthat for the regular “R” process. In this stage, the intermediate (V) isprepared via the reaction of one mole of the selected alkyl (oralkylether) amine with two moles of the ethylene oxide or other alkyleneoxide at temperature that varies preferably in the range from 160-190°C. and at pressure that preferably varies from 40-90 psig. Typically,the intermediate (V) is prepared immediately prior to its catalyzedethoxylation. However, for products based on tallow or coco amine, theStage 1 can be by-passed by using the commercially availableN,N-bis(2-hydroxyethyl)-N-alkylamine based on coco amine (Ethomeen C/12from Akzo Nobel, Varonic K-202 from Degussa) or based on tallow amine(Ethomeen T/12 or Varonic T-202).

In the second stage of the “S” process, the intermediate (V) is reactedwith additional quantity of ethylene oxide or other alkylene oxide inthe presence of a catalyst. This catalyzed ethoxylation stage involvesthe mixing of the intermediate (V) with the desired catalyst in apressure vessel, followed by the slow addition of the desired quantityof the ethylene oxide to the vessel while the temperature of the mixturein the vessel is carefully maintained in a certain range. The catalyzedethoxylation of the intermediate (V) is an exothermic reaction andcooling is required to maintain the temperature in the preferred range.

However, unlike the “R” processes that utilize a basic (hydroxide)catalyst, Stage 2 of the “S” process utilizes a Lewis Acid catalyst.Boron trifluoride is the preferred catalyst, although other Lewis acidcatalysts could be employed. Alternatively, said Lewis Acid catalyst canbe tin fluoride (SnF₄), or a boron trifluoride complex. Examples of aboron trifluoride complexes useful in the context of the presentinvention include, but are not limited to members selected from thegroup consisting of boron trifluoride-ethylene oxide, borontrifluoride-diethyl ether, boron trifluoride-dibutyl ether, borontrifluoride-tetrahydrofuran, boron trifluoride-methanol, borontrifluoride-phosphoric acid and boron trifluoride-acetic acid andmixtures thereof.

In a preferred embodiment, boron trifluoride (BF₃) is the catalyst forthe ethoxylation of alkylamine, and it is most effective when used atthe BF₃ concentration ranging from 0.04-0.07% of the weight of the finalethoxylated product.

In addition to the catalyst, temperature is a critical factor in the new“S” ethoxylation process. In the “R” processes with the base (hydroxide)catalyst, the temperature can be anywhere between 110-190° C. However,for the “S” process of the present invention, it is preferred that thetemperature be maintained in the range between 95-130° C., preferably inthe range of 110-120° C. The normal catalyzed ethoxylation reaction ofthe intermediate (IV) does not occur at temperature higher than about130° C. (possibly due to the destruction of the catalyst-ethylene oxidecomplex) or lower than about 95° C.

One of ordinary skill in the art recognizes that there are variousprocesses for making the peaked ethoxylates employed in the presentinvention and any of such ethoxylates, regardless of the method of theirpreparation, meeting the definition of degree of peaking herein areequally useful in the context of the invention.

Whereas the acid-catalyzed process (the “S” process) promotes the peakedethoxylation distribution and thus enhances the performance of theresulting ethoxylated alkylamine/alkyl ether amine, there are severaldrawbacks, including but not limited to the following that restricts itsutilization and usefulness.

-   -   The catalyst (Boron Trifluoride) is not only expensive, but also        a hazardous material. The use of this catalyst requires        elaborated equipment for its storage and charging to the        reactor.    -   The process also enhances the formation of undesired        by-products, most noticeably dioxane and (poly)ethylene glycol        derivatives (EGDs). Depending on the number of moles of ethylene        oxide used in the ethoxylation process, the dioxane content in        the ethoxylated products could be as high as 25000 ppm. Dioxane        is perceived as a hazardous material and it is desirable that it        be removed or minimized in the ethoxylated product. Because of        its reasonable volatility, dioxane can be removed, e.g., by        sparging the ethoxylation reaction product with nitrogen.        However, removal of such a high concentration of dioxane        requires additional equipment, greatly prolongs the cycle time        and reduces the product yield. The concentration of EGDs may        typically range from about 5% to about 10% by weight, much        higher than that of dioxane. While it is not a hazardous        material, the high content of EGDs lowers the concentration of        the desired ethoxylated alkylamine, and thus may adversely        affect the performance or effectiveness of the ethoxylated        product in its application. Moreover, the EGDs are of        substantially lower volatility than dioxane, and thus more        difficult to separate from the alkoxylated amine surfactant.    -   The color of the resulting ethoxylated product degrades over        time.    -   The process cannot be effectively utilized with propylene oxide.

The preferred process of the present invention, the “N” process,possesses the advantages of the above-described base-catalyzed andacid-catalyzed processes while eliminating or greatly reducing thedrawbacks inherent in same. Specially, the “N” process enables thepreparation of alkoxylated alkylamine/alkyl ether amine with the desiredpeaked alkoxylation distribution, thus ensuring optimum performance intheir respective applications. Simultaneously, the “N” process utilizesa base catalyst, preferably a hydroxide or may in some embodimentsproceed without a catalyst. As a result, the problem associated with theuse of the acid-catalyst, including high cost and hazardous property ofthe catalyst, the formation of hazardous, undesired by-products, theprolonged cycle time, and the color degradation, are greatly minimized.

In accordance with the invention, the present inventors have discoveredthat polymerization can be conducted without the necessity of utilizinga catalyst, such as a Lewis acid, calcium-based or rare earth catalystwhile achieving a more favorable peaked distribution of homologs than isfound in otherwise identical commercially available surfactants havingthe same average total of alkylene oxide substituents. The preferredprocess, the “N” process, may optionally use an alkaline catalyst whilestill preserving the favorable peaked distribution that distinguishesthe surfactant of the invention from the products of commerce. The novelprocess achieves the desired result by control of the conditions of thereaction and especially the temperature thereof. For alkoxylatedalkylamines of modest average number of alkylene oxide units, it hassurprisingly been discovered that the reaction can be conducted entirelyin the absence of any catalyst. Because the reactivity of the growingalkylene oxide chain declines with chain length, it is preferred that analkaline catalyst be used during a portion of the conversion where thetarget average alkylene oxide to amine ratio is greater than about 6.Depending on the selection of amine, selection of alkylene oxide, exactprocess conditions and nature of the process equipment available, it maybe preferable to conclude the alkoxylation in the presence of analkaline catalyst at average alkylene oxide/amine ratios of aboutgreater than about 6 or 7.

Using the ethoxylation of primary alkyl amine as an example, the processof the invention, the “N” process, can be illustrated by the followingthree stages:

-   -   1. Stage 1 of the “N” process: Uncatalyzed ethoxylation of the        primary alkylamine In this stage, the starting primary        alkylamine (II) is reacted with u moles of alkylene oxide,        typically about 2 moles of ethylene oxide at high temperature to        yield the same tertiary intermediate (III)        (N,N-bis-(2-hydroxyethyl)N-alkylamine)

-   -    The reaction temperature varies from 160-190° C. and pressure        varies from 40-90 psig. Typically, the intermediate (III) is        prepared immediately prior to its further alkoxylation. However,        for ethoxylated products based on tallow or coco amine, the        Stage 1 can be by-passed by using the commercially available        N,N-bis(2-hydroxyethyl)-N-alkylamine based on coco amine        (Ethomeen C/12 from Akzo Nobel, Varonic K-202 from Degussa) or        based on tallow amine (Ethomeen T/12 or Varonic T-202).    -   2. Stage 2 of the “N” process: Further ethoxylation of the        resulting tertiary amines under controlled temperature        conditions.    -    No catalyst is necessary in this stage, and is preferably not        used. Instead, the further reaction of the tertiary amine        intermediate (III) with a selected additional moles (v) of        ethylene oxide is promoted by the manipulation of the        ethoxylation temperature. This stage yields the second tertiary        amine intermediate (IV) with longer (CH₂CH₂O) chain length than        that of the first intermediate (III)

-   -    where a+b is greater than 2, typically greater than about 3,        more typically greater than about 4, but also typically less        than about 9 and more typically not greater than about 6. Where        the sum of a and b meets the total target average alkylene oxide        content for the ultimate surfactant product, the reaction        product characterized as “intermediate (IV)” may constitute the        final reaction product of the process. Where the ultimate target        average number of alkylene oxide units exceeds about 6 or 7, the        process preferably proceeds to stage 3.

As discovered in this invention, the peaked distribution obtained in the“N” process is possible in the stage 2 by reacting the tertiaryintermediate (III) with alkylene oxide at certain temperature in theabsence of a catalyst. Within the selected temperature range, thealkoxylation can proceed, and the absence of the catalyst facilitatesthe chain transfer between a newly alkoxylated molecule and anothermolecule of the tertiary intermediate (III), and results in the peakeddistribution.

Both the number of moles of alkylene oxide and the alkoxylationtemperature are critical factors. For the preparation of the ethoxylatedproducts, the number of the moles of ethylene oxide used in this stageis preferred to be in the range of 1-8, typically between about 2-7, forexample, in the range of 2-5. It is possible to use many sub-stageswithin stages 1 and 2 and end up with the same total EO addition. It isalso possible to combine stages 1 and 2. However one must be mindfulthat ethoxylation performed in this stage with less than 2 moles ofethylene oxide normally results in final product without peakedethoxylation distribution, while on the other hand, ethoxylationperformed in this stage with more than 7 moles of ethylene oxide resultsin significant formation of by-products. In conducting the uncatalyzedethoxylation, the temperature is preferably maintained in the range ofabout 90 to about 130° C., more preferably in the range of about 100 toabout 120° C. Ethoxylation performed at lower than 90° C. or higher than130° C. normally stops before all the ethylene oxide is consumed.

-   -   3. Stage 3 of the “N” process: Catalyzed ethoxylation    -    This stage is optional. In this stage, the second        intermediate (IV) is reacted with the remaining quantity of        alkylene oxide to yield the final product (V). Unlike the first        two stages, a catalyst is required to facilitate the        ethoxylation in this stage.

-   -    wherein u, v and w represent the moles of alkylene oxide        employed. In this optional stage, the alkoxylation is performed        using the remaining quantity of alkylene oxide in the presence        of a catalyst. Typically, the catalyzed alkoxylation in this        stage can be performed at temperature in the range of 100-190°        C., and pressure between 40-90 psig. The number of moles of        alkylene oxide used in this stage varies, depending on the total        number of moles of alkylene oxide used in the preparation (i.e.,        in all three stages). In general, to obtain maximum peaked        distribution of the ethoxylated products, the number of moles of        EO used in the third stage is maintained at the same or less        than the number of moles of EO used in the second stage. Sodium        hydroxide and potassium hydroxide are the preferred catalysts,        though other hydroxide catalysts, including but not limited to        lithium hydroxide, tetramethylammonium hydroxide, barium        hydroxide, aluminum hydroxide, magnesium hydroxide, or complexes        containing barium, magnesium and/or aluminum hydroxides, could        be used. The sodium hydroxide or potassium hydroxide is most        effective when the concentration of their active in the product        mixture is 0.05% of the batch weight or higher.

In stages 1 and 3 of the “N” process, either or both of ethylene oxideor propylene oxide is preferably employed. Ethylene oxide is thealkylene oxide of choice in stage 2 of the “N” process. In the “N”process, the number of moles (u) is preferably about 1-3, in anotherembodiment 1.5-2.4, and in still another embodiment about 2.0. Thenumber of moles (v) is generally from about 0 to about 9, in anotherembodiment 1-7, and in still another embodiment about 2-5. It isgenerally preferred that u+v is greater than or equal to 4, for example,greater than or equal to about 5 or 6. In order to achieve higher levelsof ethoxylation, i.e., where u+v is greater than about 6 or 7, stage 3with w additional moles of alkylene oxide is preferably utilized. u+v+wis generally 15 or less.

In the “N” process according to this invention, the first stage andoptional third stage are similar to the two stages of the regular (the“R” process), base-catalyzed ethoxylation processes. The second stage ofthe “N” process according to this invention is, however, the mostimportant, because it provides the desired peaked alkoxylationdistribution.

A general comparison of the “regular” or conventional process (the “R”process) for preparing tallow amine ethoxylate having at least 8 EO andthe new “N-process” of the invention for preparing same is providedbelow.

TABLE A Regular Process N Process Stage 1 Tallowamine, mole 1 1 EO,moles 2 2 Temperature, ° C. 160-180 160-180 Pressure, psig 90 maximum 90maximum Stage 2 Catalyst NaOH/KOH None Catalyst concentration, % ~0.2 —EO, moles 7.0 4 Pressure, psig 90 maximum 90 maximum Temperature, ° C.160-180  90-130 Stage 3 Catalyst — NaOH/KOH Catalyst concentration, % —EO, moles — 3 Temperature, ° C. — 160-180 Pressure, psig — 90 maximum

Since water can undergo the catalyzed reaction with ethylene oxide toyield undesired by-products, it is important that all ethoxylationstages in the “R”, “S” and “N” processes are performed under theanhydrous condition. To attain this condition, drying of the startingmaterial (alkylamine or alkyl ether amine) and the ethoxylationequipment is done by heating the material and equipment to a temperatureof 100-150° C. under nitrogen purging or vacuum, until the content ofthe water in the starting material is less than 0.1 percent, andpreferably less than 0.05 percent, of its weight.

The preferred starting alkylamines include, but are not limited to,those derived from tallow, coconut oil, soybean oil, palm kernel oil,and mixtures thereof. The preferred starting ether amines include, butare not limited to, decyl ether amine, undecyl ether amine, dodecylether amine, tridecyl ether amine, tetradecyl ether amine, hexadecylether amine, octadecyl ether amine and mixtures thereof. In a preferredembodiment, it is preferred that the starting amines be of the formula:

R—NH₂

wherein R selected from a linear or branched, saturated or non-saturatedalkyl group containing an average of 8-22 carbon atoms; for example,12-22 carbon atoms; or 16-22 carbon atoms. Here the number of carbons isexpressed as an average because amines derived from natural oilscomprise a mixture of alkyl groups of somewhat varying length. It isgenerally preferred that the weight average value of R, R¹ or R² bebetween about C₁₂ and about C₂₂. In some applications, the average valueis between about C₁₄ and about C₂₂ or between about C₁₆ and about C₂₂.In one embodiment, it is particularly preferred that the alkoxylatedalkyl(ether)amines used in the formulations of the invention be derivedfrom primary amines having a molecular weight greater than about 200.Amines wherein the alkyl substituent contains between 16 and 18 carbonatoms may be especially advantageous, e.g., tallowamines which offersignificant economic and commercial advantages in applications such asherbicidal formulations. Alkoxylated alkylamine and alkoxylatedetheramine surfactants as prepared by the preferred “N” process of theinvention have not only a peaked distribution of desired homologs butalso relatively low concentrations of dioxane, EGDs and other byproductsthat may be detrimental to the intended end use. The dioxane contentafter a stripping step is typically not greater than 400 ppm, moretypically not greater than 300 ppm, and still more typically not greaterthan 200 ppm, while the total EGDs content, including a vinylpolyethylene glycol component, is less than about 5% by weight, moretypically not greater than about 4% by weight, and most typically notgreater than about 3% by weight, of the resulting ethoxylated product.

To compare alkylene oxide distribution in an alkoxylated alkylamine, useof degree of peaking is helpful. The degree of peaking (Σ3) is definedas the sum of the areas for the adjacent three most prevalent peaks. Therelative degrees of peaking of ethoxylates prepared according to theprocess of the present invention was measured and compared to theircounterparts prepared via conventional base-catalyzed ethoxylation.

For degree of peaking determinations, area percent determined by gaschromatography (GC) was used. The degree of peaking is expressed as aweight percentage (%). The higher the weight percentage, the more peakedthe molecular weight distribution. The formula and method fordetermination of molecular weight distribution can be found in NarrowAlcohol Ethoxylates, Annual Surfactants Reviews, vol. 2, Ed. D. R. Karsa(1999), and, with some modification, can be adapted for alkoxylatedalkylamines.

The alkoxylated alkyl amines having peaked distribution of the presentinvention are further characterized in having peaked distributiondefined by a degree of peaking at least 5% greater than the degree ofpeaking in the distribution of a conventional alkoxylated aminecomposition prepared via conventional base catalysis. Typically, thedegree of peaking may be at least 6% greater, preferably at least 7%greater than the degree of peaking in the distribution of a conventionalalkoxylated amine composition prepared via conventional base catalysis,for which the conditions are described in Table A. In still otherembodiments, the degree of peaking at least 10% greater than that foundin the distribution of a conventional peaked alkoxylated aminecompositions prepared via conventional base catalysis.

A normalized peaking index may be defined as PI=(W₀/2)^(1/2)(Σ3) whereinPI is the peaking index, Σ3 is the sum of the weight percentages of thethree most prevalent homologs, and W₀ is the weight average ratio ofalkylene oxide units per molecule in the alkoxylated alkylamine oralkoxylated etheramine composition. Preferably the PI is greater than100, more preferably greater than about 102.

The preferred alkoxylated alkylamines with peaked distribution include,but are not limited to ethoxylated tallow amine with 3 to 15 EO,ethoxylated coco amine with 3 to 15 EO, and mixtures thereof. Preferredalkoxylated alkyl ether amines with peaked distribution include, but arenot limited to ethoxylated dodecyl ether amine with 3 to 15 EO,ethoxylated tridecyl ether amine with 3 to 15 EO, ethoxylated tetradecylether amine with 3 to 15 EO, ethoxylated hexadecyl etheramine with 3 to15 EO, ethoxylated octadecyl etheramine with 3 to 15 EO and mixturesthereof. In the formulation of aqueous glyphosate salt concentrates,several discrete ranges of EO/amine ratio are commonly used, e.g.: (i) asurfactant having a relatively low ratio in the range of about 3 toabout 6 EO/amine, most typically about 5; (ii) a surfactant having anintermediate EO/amine ratio in the range between about 8 and about 12EO/amine, more typically about 9 to about 11, most typically about 10;and (iii) a surfactant having a relatively high EO/amine ratio in therange between about 12 and about 18 EO/amine, more typically betweenabout 13 and about 17, most typically about 15.

Though not required, a solvent that is inert toward the reaction withethylene oxide can also be used to improve the handling of the startingalkylamine or the resulting ethoxylated product, or to meet the minimuminitial volume of material that is required for proper mixing actionwith ethylene oxide as required for each ethoxylation reactor. Aromaticsolvents, such as xylene, toluene, alkylbenzenes such as ethylbenzene,hexylbenzene, dodecylbenzene, alkylnaphthalenes such as methyl anddimethylnaphthalene, isopropyl- and di-isopropylnaphthalene, orcommercial aromatic solvents, such as Aromatic Solvent 100, 150 or 200available at ExxonMobil, or organic ethers, such as dibutyl ether . . .and the like are suitable solvents for the process of this invention.

Glyphosate formulations generally require one or more adjuvants in orderto boost their herbicidal efficacy. The proportion of adjuvant employedin the formulation is typically 10% or higher, in order to achievesignificant boosting effect. The cost associated with the use of theadjuvants in glyphosate formulations is significant. Therefore, there isan ever increasing need to find a more effective and economical adjuvantfor glyphosate.

Glyphosate is an acid with a very limited solubility in water whilesalts of glyphosate have very high solubility in water. Therefore,glyphosate formulations usually employ salts of glyphosate. Many typesof counterions have been used commercially in glyphosate products. Theyinclude isopropylammonium (IPA⁺), monoethanolammonium (MEA⁺),diethanolammonium (DEA⁺), triethanolammonium (TEA⁺), sodium,trimethylsulfonium (TMS⁺), potassium (K⁺), and ammonium (NH₄ ⁺).Potassium glyphosate is a preferred glyphosate salt employable in thecontext of the invention.

For liquid aqueous glyphosate concentrates, glyphosate loading ispreferably 360 g ae/l or higher. It is known to those skilled in the artthat many biologically useful surfactants cannot be reliablyincorporated into glyphosate formulations at glyphosate, a.e.,concentrations greater than 360 g/L without risk of phase separation atelevated temperatures. For such aqueous concentrates, therefore, anobjective is to select a highly efficacious surfactant that can be usedat relatively low concentration in glyphosate formulations to improvesignificantly the herbicidal efficacy of glyphosate. It is particularlypreferred to identify and select a surfactant that can be formulatedinto stable glyphosate formulations including potassium and ammoniumsalts of glyphosate, at 470-600 g ae/l.

The present invention meets such objective in providing glyphosateformulations having favorable and/or improved stability and herbicidalefficacy comprising, as an adjuvant, at least one peaked distributionalkoxylated alkylamine surfactant. The aforementioned adjuvant can beemployed at low concentration and is stable in various salts ofglyphosate even at very high glyphosate concentration.

It is generally preferred that the total number of moles (2x+y+y′+z+z′)of alkylene oxide used for the alkoxylation of the alkyl (or alkylether)amine varies from 3-15; typically from 3-12, in many instances from 3-9.

Preferred examples of ethoxylated alkylamines according to the inventionare ethoxylated versions based on cocoamine, tallow amine, soya amine,oleyl amine, palm amine and mixtures thereof.

In various exemplary embodiments, the ethoxylated amine of the inventionis selected from the group consisting essentially of ethoxylatedtallowamine, ethoxylated cocoamine, ethoxylated alkyletheramine such astridecyletheramine, each having from 3 to 15 moles of EO, and mixturesthereof.

A typical stable liquid glyphosate formulation according to theinvention has a concentration of glyphosate in the range of 360-600 gae/l, preferably 450-580 g ae/l, and the ratio of glyphosate (wt % ae)to the ethoxylated alkylamine surfactant with peaked distribution isbetween 2:1 to 25:1. Typically, ratio of glyphosate (wt % ae) to theethoxylated alkylamine surfactant with peaked distribution is between2.5:1 to 20:1, more typically between 3:1 to 15:1.

The ethoxylated alkylamine with peaked distribution of the invention isexemplified by having an enhanced cloud point of about 8 degrees in54.8% K-glyphosate formulation with 10% peaked cocoamine-5EO surfactantwhen compared to the regular cocoamine-5EO having the same carbon chainlength and average EO chain length prepared via conventional basecatalysis.

The present invention encompasses not merely formulations of glyphosate,but also relates to other herbicidal compositions comprising at leastone herbicidal active, and at least one surfactant, wherein said atleast one surfactant comprises the alkoxylated alkylamine and/oralkylether amine with peaked distribution of the invention. A herbicidalcomposition according to the invention can optionally comprise otheradditives such as ammonium sulfate, potassium sulfate, potassiumchloride, sodium sulfate, urea, glycols, or mixtures thereof. Acontemplated composition can optionally include a synergist, quick-burnadditive, humectant, co-herbicide, dye, pigment, corrosion inhibitor,thickener, dispersing agent, calcium sequestrant, defoamer, antifreeze,pour-point depressant, process aids, or mixture thereof. Combinations ofglyphosate salts and co-herbicide salts are specifically contemplated bythe present invention. Preferably, additives used in glyphosatecompositions of the present invention possess sufficient solubility ordispersibility in a concentrated aqueous potassium glyphosate solutionat a pH of from about 4 to about 7 to allow desired concentrations to beattained.

Where a co-herbicide is included in the formulation, it is preferredthat the co-herbicide be water-soluble, and more preferred that it beincluded in the form of an ammonium or potassium salt. Examples ofsuitable co-herbicides are the ammonium salts of acifluorfen, asulam,benazolin, bentazon, bialaphos, bromacil, bromoxynil, chloramben,clopyralid, 2,4-D, 2,4-DB, pelargonic acid, dalapon, dicamba,dichlorprop, diclofop, endothall, fenac, fenoxaprop, flamprop,fluazifop, fluoroglycofen, fomesafen, fosamine, glufosinate, haloxyfop,imazameth, imazamethabenz, imazamox, imazapyr, imazaquin, imazethapyr,ioxynil, MCPA, MCPB, mecoprop, methylarsonic acid, naptalam, nonanoicacid, picloram, sulfamic acid, 2,3,6-TBA, TCA and triclopyr. A preferredco-herbicide is the salt of glufosinate.

Formulations of the present invention may be generally prepared bymixing the glyphosate salt solution, prepared as outlined above,together with other ingredients in a suitable mixing vessel withagitation, such as a blender.

A typical aqueous concentrate according to the invention containsglyphosate acid equivalent in the range of from 30 to 45%, and fromabout 1.2 to about 22.5% surfactant. For application to a field incontrol of weeds, a typical formulation according to the inventioncontain glyphosate acid equivalent in the range of from about 0.1 to18%, typically 0.1 to 5 wt. %, more typically 0.2 to 3%, most commonly0.5 to 2 wt. %. However, stronger mixtures, e.g., in the range fromabout 2 to about 15% surfactant may be desirable for some applications.

This invention also relates to a herbicidal method of using acontemplated composition in an amount effective to kill or controlunwanted vegetation by diluting the composition in water and applyingthe diluted composition to foliage of the vegetation to be killed orcontrolled.

The glyphosate formulation of the invention should be applied to plantfoliage at an application rate sufficient to give the desired effect.Application rates are usually expressed as amount of glyphosate a.e. perunit area of land treated, e.g. grams a.e. per hectare (g a.e./ha). Whatconstitutes a “desired effect” varies according to the standards andpractice of those who investigate, develop, market and use glyphosateproducts. For example, the amount of glyphosate a.e. applied per unitarea to give, consistently and reliably, at least 85% control of a plantspecies as measured by growth reduction or mortality is often used todefine a commercially effective rate.

Preferred compositions of the invention provide enhanced herbicidalefficacy by comparison with commercial standard formulations ofglyphosate “Herbicidal efficacy,” as used herein, refers to anyobservable measure of control of plant growth, which can include one ormore of the actions of (1) killing, (2) inhibiting growth, reproductionor proliferation, and (3) removing, destroying, or otherwise diminishingthe occurrence and activity of plants.

The selection of application rates that are biologically effective for aspecific glyphosate formulation, such as a formulation of the presentinvention, is within the skill of the ordinary agricultural scientist.Those of skill in the art will likewise recognize that individual plantconditions, weather and growing conditions, as well as the specificformulation selected, will influence the degree of biologicaleffectiveness achieved in practicing this invention. Useful applicationrates can therefore depend upon all of the above conditions. Muchinformation is known about appropriate application rates for glyphosateformulations in general. Over two decades of glyphosate use andpublished studies relating to such use have provided abundantinformation from which a weed control practitioner can select glyphosateapplication rates that are herbicidally effective on particular speciesat particular growth stages in particular environmental conditions.

Various application methods may be employed including broadcastspraying, directed spraying or wiping the foliage with a dilutedcomposition of this invention. Depending on the degree of controldesired, the age and species of the plants, weather conditions and otherfactors, typically the glyphosate application rate is a herbicidallyeffective amount of about 0.1 to about 10 kg a.e./ha and preferably fromabout 0.25 to about 2.5 kg a.e./ha, although greater or lesser amountsmay be applied.

The alkoxylated alkylamine with peaked distribution of the invention ispreferably selected so that an aqueous concentrate containingK-glyphosate wt % a.i. of 54.8 (“wt % a.i.” means weight percent activeingredient, in this case K glyphosate) and the peaked distributionalkoxylated alkylamine at a concentration of 10 wt % exhibits a cloudpoint greater than about 66° C. More particularly, in a potassiumglyphosate concentrate of such composition, a formulation containing 10wt % of a peaked distribution cocoamine 5EO surfactant has a cloud pointapproximately 8° C. higher than the otherwise identical formulationcontaining 10 wt % of a conventional cocoamine 5EO surfactant made byconventional base catalysis. Other otherwise identical K glyphosatesolutions containing conventional alkoxylated alkylamine surfactantstypically possess a cloud point of room temperature, or slightly aboveroom temperature.

A typical stable liquid glyphosate formulation according to theinvention has a concentration of glyphosate in the range of 360-600 gae/l, preferably 450-580 g ae/l, and the ratio of glyphosate (wt % ae)to the ethoxylated alkylamine surfactant with peaked distribution isbetween 2:1 to 25:1. Typically, ratio of glyphosate (wt % ae) to theethoxylated alkylamine surfactant with peaked distribution is between2.5:1 to 20:1, more typically between 3:1 to 15:1. In exemplaryembodiments of such formulations, the ratio of glyphosate (wt % ae) tothe alkoxylated amine surfactant with peaked distribution may be between3.5:1 to 8:1, or in particular instances between 4:1 to 6:1.

Although it is an important objective of the invention to providesurfactants suitable for producing stable high load aqueous liquidconcentrates comprising potassium and ammonium glyphosate, it will beunderstood that the surfactants of the invention can also be used insolid glyphosate acid and glyphosate salt formulations. Ammonium anddiammonium glyphosate, in particular are often supplied in dry, solidgranular form. Dry formulations comprising sodium salts of glyphosateand or comprising glyphosate acid are also known. In this context, itwill be understood that the term “stable” applies in the sense thatformulations comprising the surfactants of the invention are formulatedso as to avoid excessive stickiness and/or syneresis.

The present inventors have established that superior properties areexhibited by the surfactants prepared by the novel processes describedherein, and in particular that surfactants of the invention aredistinguished by the distinctly higher cloud points compared to thecloud points exhibited by exemplary aqueous glyphosate salt concentrateswhich contain these surfactants. Thus, for example, the surfactants ofthe invention may be characterized by reference to an aqueousconcentrate containing potassium glyphosate salt in a concentration of54.8 wt. % of the active ingredient salt (“a.i.”). Such formulationcontaining an alkoxylated alkylamine or alkoxylated etheramine of theinvention has a cloud point at least 3° C. higher, preferable at least5° C. higher, and in another embodiment at least 7° C. higher than thatof substantially similar glyphosate formulations containing conventionalnon-peaked ethoxylated alkylamines having the same distribution ofcarbon-chain length, and the same average EO chain length, prepared byconventional base catalysis, which is hereinafter defined as catalysisaccording to the conditions described in Table A, as the surfactantcomponent.

Additionally, where alkoxylation is conducted in the substantial absenceof catalyst until the average extent of substitution, i.e., the weightaverage value of the sum of (2x+y+y′+z+z′) sometimes referred to hereinas “W₀,” has reached a value of 4, 5, 6, 7, 8 or 9, the surfactants ofthe invention contain relatively lower amounts of dioxane and EGDsincluding, but not limited to vinyl polyethylene glycols.

It has been established that superior properties are exhibited by thesurfactants prepared by the novel processes described herein, and inparticular that surfactants of the invention are distinguished by thedistinctly higher cloud points that are exhibited by exemplary aqueousglyphosate salt concentrates which contain these surfactants. Thus, forexample, the surfactants of the invention may be characterized bycomparison of the cloud points exhibited by a pair of reference aqueousconcentrates, each consisting of potassium glyphosate salt in aconcentration of 540 g/L, a.e., 5.5 wt. % alkoxylated alkyl(ether)aminesurfactant having EO groups, and 4.5 wt. % bis(2-hydroxyethyl)cocoamine.A first such reference formulation containing an adjuvant surfactant ofthe invention exhibits a cloud point at least about 3° C. higher thanthe cloud point of a second reference formulation of identicalcomposition but containing 5.5 wt. % of a reference surfactant ratherthan the adjuvant surfactant of the invention. For purposes of thiscomparison, the surfactant of the invention and the reference surfactantare each derived from a primary amine having a molecular weight of atleast 200 (thus have the same distribution of carbon chain length), andhave the same value of W₀ as defined herein. The reference surfactant isprepared by an NaOH-catalyzed reaction of the amine with alkylene oxideconducted under conventional conditions described hereinbelow.

Additionally, where alkoxylation is conducted in the substantial absenceof catalyst until the average extent of substitution, i.e., the numberaverage value of the sum of (2x+y+y′+z+z′) sometimes referred to hereinas “W₀,” has reached a value of 4, 5, 6, 7, 8 or 9, the surfactants ofthe invention preserves a relatively low concentration of dioxane, vinylPEGs, and other EGDs.

It has further been observed that the frequency distribution of homologsin the surfactants of the invention typically differs in various waysfrom the frequency distribution for the homologs of the conventionalalkoxylated alkylamine and alkoxylated etheramine surfactants ofcommerce. For example, in most instances, the degree of peaking ishigher in the surfactants of the invention. The degree of peaking isdefined as the sum of the number percentages of the three most prevalenthomologs. For the surfactants of the invention, this sum, sometimesreferred to herein as “Σ3,” is in most instances higher by an incrementof at least about 2 wt. %, more typically at least about 3%, often atleast about 4 wt. %, 5 wt. %, or 6 wt. %, basis the entire surfactant,than the Σ3 value for a reference mixture of homologs having the samevalue of W_(o), the same frequency distribution with regard to thenumber of carbon atoms in the substituent R, and the same identity of X,Y and Z as the surfactant of the invention. It has further been notedthat the ratio of the degree of peaking for the surfactants of theinvention to the corresponding reference mixture is typically at leastabout 1.05, more typically at least about 1.07 or 1.08, and in amajority of cases at least about 1.10. For purposes of this comparison,the reference mixture is an alkoxylated alkylamine or etheraminecharacteristic of the prior product of commerce, and is prepared byNaOH-catalyzed reaction of RNH₂ with alkylene oxide conducted entirelyunder autogenous pressure up to 90 psig at a temperature of 160° to 180°C. and an NaOH concentration of 0.2 wt. %. It will be understood that,while not all commercial surfactants are necessarily prepared under theexact conditions here specified for the “reference mixture,” asurfactant of the invention which has a degree of peaking at least about3 wt. % higher (or even 2 wt. % higher) than this reference compositionwill in at least most instances also have a degree of peaking higherthan known commercially available alkoxylated amine surfactants whichhave the same values of W₀ and Σ3 as the inventive and referencesurfactants, the same frequency distribution with regard to the numberof carbon atoms in the substituent R, and the same identify of X, Y andZ.

The degree of peaking varies with value of W₀, generally inverselytherewith, For purposes of comparison, the degree of peaking may benormalized across a range of values for W₀ by definition of a “peakingindex,” computed by multiplying Σ3 by a function of W₀. For example apeaking index may conveniently be defined as (W₀/2)^(1/2)(Σ3). As sodefined, the peaking index for the surfactant of the invention istypically greater than the peaking index for the corresponding referencemixture by an increment of at least about 3, more typically at leastabout 5, 6, or 8%. The ratio of the peaking index for the surfactants ofthe invention to the peaking index for the corresponding referencesurfactants is typically at least about 1.05, more typically at leastabout 1.07 or 1.08, and in most instances at least about 1.10.

However, it has further been observed that the homolog frequencydistribution pattern varies somewhat among the surfactants of theinvention, as it also does among the surfactants of the commerce. In alimited number of instances, analyses of the surfactants of theinvention have indicated a degree of peaking and peaking index that haveappeared to be actually lower than those of the comparative referencemixture, yet the novel surfactants still exhibit superior propertieswith respect to the cloud point of glyphosate salt concentrates. It ispossible that these aberrant results have been attributable toanalytical error, but also possible that they accurately reflect thesamples analyzed.

Even though not all surfactants of the invention are necessarilydistinguished from the corresponding reference mixture or product ofcommerce by the degree of peaking or the peaking index, the homologdistribution for the surfactants of the invention also typically differsfrom the distribution for conventional alkoxylated surfactants of theprior art with respect to certain other characteristics. Among these arewhat may referred to as the “tailing index” and the “tilt ratio.” Withregard to stability of aqueous glyphosate salt concentrates, especiallypotassium or ammonium salt concentrates, it is generally preferred thata surfactant of given value for W₀ have a relatively low concentrationof homologs whose degree of substitution, i.e., the value of(2x+y+y′+z+z′), is significantly greater than W₀. Generally it ispreferred that there not be a significant fraction of homologs whosenumber % prevalence (W_(i)) excess 1.5(W₀). For this purpose a tailingindex may be defined as either β₁, β₂, β₃, β₁₂, or β₂₃ where:

-   -   β₁ is the sum of the number percentages of homologs W_(i) from        i=k to infinity where W_(i) is the number percentage of the        homolog in which i equals the sum of the number of alkylene        oxide substituents (2x+y+y′+z+z′)_(i);    -   β₂ is the sum of the number percentages of homologs W_(i) from        i=k+1 to infinity;    -   β₃ is the sum of the number percentages of homologs W_(i) from        k+2 to infinity;    -   β₁₂=β₂+[(k+1)−W₀]W_(k);

β₂₃=β₃+[(k+1)−W₀]W_(k+1); and

-   -   k is an integer such (W₀−1)≦k≦(W₀)<(k+1).

Related to the tailing index is a parameter that may be defined as thetilt ratio, a quotient of the sum of proportions of homologs havingrelatively low values of (2x+y+y′+z+z′) over the sum of proportions ofhomologs having relatively high values for (2x+y+y′+z+z′). For example,an overlapping tilt ratio may be defined as α₂₃/β₁₂ or α₂₃/β₂₃ where:

α₂ is the sum of the number percentages of homologs W_(i) from i=2 to k

α₂₃=α₂+(W₀−k)W_(k+1)

and β₁, β₂, β₁₂, and β₂₃ are defined above, in which case α₂₃/β₂₃ maypreferably be greater than about 1.42. It has also been observed thatthe tilt ratio varies with the value of W₀, so that: where W₀ is between3 and 4.5, the tilt ratio α₂₃/β₂₃ is at least about 1.90; where W₀ isbetween 4.5 and 5.5, the tilt ratio α₂₃/β₂₃ is at least about 1.85;where W₀ is between 5.5 and 6.5, the tilt ratio α₂₃/β₂₃ is at leastabout 1.75; where W₀ is between 6.5 and 8.5, the tilt ratio α₂₃/β₂₃ isat least about 1.40; where W₀ is above 8.5, the tilt ratio α₂₃/β₂₃ is atleast about 1.42. Other empirical functions may provide alternativedefinitions of tailing index, tilt ratio and peaking index.

Generally, the tilt ratio α₂₃/β₂₃ differs from the same ratio for thecorresponding reference mixture by an increment of at least about +0.08,more typically at least about +0.10, and in most instances at leastabout 0.15. The ratio of the tilt ratio for the surfactant of theinvention to the tilt ratio for the reference mixture is ordinarily atleast about 1.05, more typically at least about 1.0, and in a majorityof cases 1.15.

Because the peaking indices, tailing indices and tilt ratios reflectempirical observations of the surfactants of the invention vs. thecomparative reference mixtures that are indicative of the alkoxylatedalkylamines and etheramines of commerce, it will be understood thatthere are variations from specimen to specimen whereby the range ofvalues for the novel surfactants and the range of values for thereference mixtures and commercial surfactants can at least potentiallybe found to overlap with regard to at least one of these indices andperhaps in some instances with all of them. At the time of thisapplication, that matter has not been fully explored. Thus, it isimportant to understand that the fundamental differences between thesurfactants of the invention and those of the prior art is found intheir respective effect on the cloud points of aqueous glyphosate saltconcentrates, especially those comprising potassium and ammonium salts;and, of course, in the processes by which they are respectivelyprepared. In preferred embodiments, the surfactants of the inventionalso differ from prior art surfactants prepared by Lewis acid catalysiswith respect to the concentration of dioxane, vinyl PEG and other EGDs.

Nevertheless, it is believed that, in general, the surfactants of theinvention differ from the reference mixtures, and therefore from theprior art commercial surfactants, with respect to at least one of theparameters discussed above, i.e., the degree of peaking, the peakingindex, the tailing index, and/or the tilt ratio, or by some combinationthereof; at that these parameters have value in helping to characterizethe surfactants of the invention.

The invention will now be illustrated by the following nonlimitingexamples.

Example 1 Preparation of Ethylated Coco Amine by the “S” Process Using 5Moles of Ethylene Oxide

Distilled coco amine (520 g, 2.6 moles) was charged to a one-gallonstainless steel pressure vessel and then heated at 130° C. undernitrogen purging for 30 minutes to reduce its moisture content to lessthan 0.1%. Ethylene Oxide (230 g, 5.23 moles) was then added to thepressure vessel over a period of 40 minutes while the temperature wasmaintained at 150-160° C. Following a 30-minutes period of digestion,the reaction mixture was purged with nitrogen to remove the trace ofethylene oxide and analyzed. Its Total Amine Value is 194 mg KOH/g,indicating that the 2.00 moles of ethylene oxide has been consumed forthe ethoxylation of 1 mole of coco amine.

The product mixture was then cooled to 100° C. BoronTrifluoride-Phosphoric Acid complex (1.70 g) was then injected to thereactor. The mixture was then heated to 110° C., then ethylene oxide(330 g, 7.5 moles) was added to the reactor over a 90 minutes periodwhile the pressure was maintained at 50 psig. An exothermic reactionoccurred; cooling was applied to maintain the temperature in the rangeof 110-120° C. throughout the addition of ethylene oxide. Uponcompletion of the ethylene oxide addition, the reaction mixture wasdigested for one hour at the same temperature and pressure. Analysisshowed that the product mixture contains about 2000 ppm of dioxane. Acombination of nitrogen purging and the in injection of water (togenerate steam in situ) was then applied for two hours to strip thedioxane from the product mixture. The product mixture was then dried bynitrogen purging at 120° C. for one hour to reduce its moisture contentto less than 0.5%. Its TAV is 133.4 mg KOH/g, indicating that a total of5.0 moles of ethylene oxide have been consumed for the ethoxylation eachmole of coco amine.

FIG. 2 illustrates the homologs distribution of the resulting product(C/15S) and of the Ethomeen C/15, its commercially available counterpartthat is prepared by the regular, hydroxide-catalyzed ethoxylation of thecocoamine with the same number of moles (5) of the ethylene oxide. Thepeaked distribution of the homologs is indicated by their higherconcentration (weight %) at the middle of the distribution range. As isshown in FIG. 2, the most prevalent EO adduct is 4 in both processeseven though 5 EO is added. The degree of peaking is 68 for C/15S and 60for C/15.

Examples 2 Preparation of Ethoxylated Cocoamine by the “S” Process Using6 Moles of Ethylene Oxide

In this example, the first stage (ethoxylation of distilled cocoaminewith 2 moles of ethylene oxide) was by-passed. The commerciallyavailable Ethomeen C/12 was used as the starting material. Theethoxylated of the Ethomeen C/12 with 4 moles of ethylene oxide in thisexample was catalyzed by Boron Trifluoride-Diethyl Ether Complex.

Ethomeen C/12 (750 g, 2.59 moles) was charged to a one-gallon stainlesssteel pressure vessel and then heated at 130° C. under nitrogen purgingfor 30 minutes to reduce its moisture content to less than 0.1%. It wasthen cooled 100° C. Boron Trifluoride-Diethyl Ether complex (1.56 g) wasthen injected to the reactor. The mixture was then heated to 110° C.,then ethylene oxide (460 g, 10.45 moles) was added to the reactor over a60 minutes period while the pressure was maintained at 50 psig. Anexothermic reaction occurred; cooling was applied to maintain thetemperature in the range of 110-120° C. throughout the addition ofethylene oxide. Upon completion of the ethylene Oxide addition, thereaction mixture was digested for one hour at the same temperature andpressure. Analysis showed that the product mixture contains about 3000ppm of dioxane. A combination of nitrogen purging and the in injectionof water (4% of batch weight, to generate steam in situ) was thenapplied for two hours to strip the dioxane from the product mixture. Theproduct mixture was then dried by nitrogen purging at 120° C. for onehour to reduce its moisture content to less than 0.5%. Its TAV is 123.7mg KOH/g, indicating that a total of 5.8 moles of ethylene oxide havebeen consumed for the ethoxylation each mole of the coco amine.

FIG. 3 illustrates the homologs distribution of the resulting product(C/16S) and of the Ethomeen C/16, its commercially available counterpartthat is prepared by the regular, hydroxide-catalyzed ethoxylation of thecocoamine with the same number of moles (6) of the ethylene oxide. Thepeaked distribution of the homologs is indicated by their higherconcentration (weight %) at the middle of the distribution range. As isshown in FIG. 3, the most prevalent EO adduct is 4 in both processeseven though 6 EO is added. The degree of peaking is 58 for C/165 and 49for C/16.

Example 3 Compatibility of Ethoxylated Alkylamine with PotassiumGlyphosate

Compatibility of cocoamine-5EO (C/15), cocoamine-6EO (C/16), andtallowamine-10EO (T/20) by the new BF3-catalyzed process (the “S”process) and by the “N” process were compared with the regular,hydroxide-catalyzed process (the “R” process) in potassium glyphosatesolution. Solution Cloud Point was used to compare the solutions. Asshown in Table 1, glyphosate formulas containing 10% ethoxylatedalkylamine made by the peaked process have higher Cloud Point,indicating that it is more stable than the formula containing theethoxylated alkylamine made by conventional processes.

Cloud Point Method

A sample of a stable, transparent formulation is first heated in a 90+°C. water bath. As the temperature of the sample increases “cloudiness”is usually observed. Heating is continued until the cloudiness of thesolution is maximized, i.e., the polymeric components dissolved in theformulation precipitate out of solution. If the temperature exceeds 90°C. and no cloudiness is apparent, the result is recorded as CP>90° C.

Next, the solution is slowly cooled by removing the formulation samplefrom the water bath while gently agitating the sample (e.g., by stirringwith a thermometer) and monitoring the dissolution of the suspendedpolymeric material. When the cloud point temperature is reached thetransition increases dramatically due to the remixing or dissolution ofthe precipitated or polymeric phase.

The temperature at which the formulation sample returns to transparencyis recorded as the cloud point for that sample. This analysis isrepeated on several different samples. The average observed cloud pointof these samples is calculated and reported as the cloud point of theparticular formulation tested.

TABLE 1 Cloud Point of concentrated glyphosate formula containingethoxylated alkylmines prepared from the regular and the peakedprocesses. CLOUD POINT K- (° C.) glyphosate Surfactant Surfactant PeakedComparative wt % a.i. wt % Description Process “R” Process 54.8 10Cocoamine-5EO 66 (“N”) 58 54.6 10 Cocoamine-6EO 59 (“S”) RT separate*54.6 10 Cocoamine- 44 (“S”) RT separate* 2EO:Tallowamine 10EO = 35:65(wt./wt. Ratio) 40.3 10 Tallowamine-9EO 75 (“N”) 71 54.6 9 Cocoamine- 58(“N”) 52 2EO:Tallowamine 9EO = 35:65 (wt./wt. Ratio) *RT—roomtemperature (at room temperature the surfactant is not sufficientsoluble to avoid phase separation) Water was used to balance thesolutions to 100 wt %.

Example 4 Preparation of Ethoxylated Coco Amine Using 6 Moles of EO (the“N” Process)

Stage 1: Distilled coco amine (520 g, 2.6 moles) was charged to aone-gallon stainless steel pressure vessel and then heated at 130° C.under nitrogen purging for 30 minutes to reduce its moisture content toless than 0.1%. Ethylene Oxide (230 g, 5.23 moles) was then added to thepressure vessel over a period of 40 minutes while the temperature wasmaintained at 150-160° C. Following a 30-minute period of digestion, thereaction mixture sampled and analyzed. Its Total Amine Value is 194 mgKOH/g, indicating that the 2.00 moles of ethylene oxide has beenconsumed for the ethoxylation of 1 mole of coco amine.

Stage 2: The product mixture was then cooled to 115° C. Ethylene oxide(320 g, 7.27 moles) was then added to the pressure vessel over a period50 minutes, while the temperature was maintained at 115-125° C.Following a 60-minute period of digestion, the reaction mixture waspurged with nitrogen, then samples and analyzed. Its Total Amine Valueis 138 mg KOH/g, indicating that in this stage, 2.7 moles of ethyleneoxide has been consumed for the ethoxylation of 1 mole of coco amine.

Stage 3: Potassium hydroxide (2.50 g, 0.02 moles) was charged to thepressure vessel. The reaction mixture was purged with nitrogen, thenheated at 150° C. for 30 minutes under nitrogen purging to reduce itsmoisture content to less than 0.1%.

Ethylene Oxide (150 g, 3.4 moles) was then added to the pressure vesselover a period of 20 minutes while the temperature was maintained at150-160° C. Following a 30-minute period of digestion, the reactionmixture was purge with nitrogen to remove the trace of unreactedethylene oxide, then cooled to 50° C. and discharged. Its TAV is 120 mgKOH/g, indicating that a total of 6.1 moles of ethylene oxide have beenconsumed for the ethoxylation each mole of coco amine. The content ofdioxane (about 150 ppm) and EGDs (about 2.5%) of the final product aremuch lower than the content of dioxane (about 5000 ppm) and EGDs (about7.5%) of its counterpart made by the acid-catalyzed process.

FIG. 4 illustrates the homologs distribution of the resultingethoxylated product (6NP) and of its counterpart that is prepared by theregular, hydroxide-catalyzed ethoxylation of the coco amine with thesame number of moles (6) of the ethylene oxide (6RP) that has the sameTotal Amine Value. The degree of peaking is 60 for 6NP and 49 for 6RP,indicating that the 6NP product made by the new process possesses apeaked ethoxylation distribution.

Example 5 Preparation of Ethoxylated Coco Amine by the “N” Process Using8 Moles of Ethylene Oxide

Stage 1: Distilled coco amine (520 g, 2.6 moles) was charged to aone-gallon stainless steel pressure vessel and then heated at 130° C.under nitrogen purging for 30 minutes to reduce its moisture content toless than 0.1%. Ethylene Oxide (230 g, 5.23 moles) was then added to thepressure vessel over a period of 40 minutes while the temperature wasmaintained at 150-160° C. Following a 30-minute period of digestion, thereaction mixture sampled and analyzed. Its Total Amine Value is 194 mgKOH/g, indicating that the 2.00 moles of ethylene oxide has beenconsumed for the ethoxylation of 1 mole of coco amine.

Stage 2: The product mixture was then cooled to 115° C. Ethylene oxide(460 g, 10.46 moles) was then added to the pressure vessel over a period75 minutes, while the temperature was maintained at 115-125° C.Following a 60-minute period of digestion, the reaction mixture waspurged with nitrogen, then samples and analyzed. Its Total Amine Valueis 122 mg KOH/g, indicating that in this stage, 3.9 moles of ethyleneoxide has been consumed for the ethoxylation of 1 mole of coco amine.

Stage 3: Potassium hydroxide (3.0 g, 0.025 moles) was charged to thepressure vessel. The reaction mixture was purged with nitrogen, thenheated at 150° C. for 30 minutes under nitrogen purging to reduce itsmoisture content to less than 0.1%. Ethylene Oxide (465 g, 6.02 moles)was then added to the pressure vessel over a period of 20 minutes whilethe temperature was maintained at 150-160° C. Following a 30-minuteperiod of digestion, the reaction mixture was purge with nitrogen toremove the trace of unreacted ethylene oxide, then cooled to 50° C. anddischarged. Its TAV is 101 mg KOH/g, indicating that a total of 8.08moles of ethylene oxide have been consumed for the ethoxylation eachmole of coco amine. The content of dioxane (about 200 ppm) and EGDs(about 2.7%) of the final product are much lower than the content ofdioxane (about 8000 ppm) and EGDs (about 9.0%) made by theacid-catalyzed process.

FIG. 5 illustrates the homologs distribution of the resultingethoxylated product (8NP) and of its counterpart that is prepared by theregular, hydroxide-catalyzed ethoxylation of the coco amine with thesame number of moles (8) of the ethylene oxide (8RP). The degree ofpeaking is 51 for 8NP and 42 for 8RP, indicating that the 8NP productmade by the new process possesses a peaked ethoxylation distribution.

Example 6 Preparation of Ethoxylated Coco Amine Using 9 Moles ofEthylene Oxide

In this experiment, the Stage 1 Ethoxylation (non-catalyzed reaction ofcoco amine with 2 moles of ethylene oxide) was by-passed. Instead, thecommercially available Ethomeen C/12, having a Total Amine Value of 195mg KOH/g, was used as the starting material.

Stage 2: Ethomeen C/12 (700 g, 2.43 moles) containing less than 0.1%water was charged to a one-gallon stainless steel pressure vessel,purged with nitrogen then heated to 115° C. Ethylene oxide (450 g, 10.22moles) was then added to the pressure vessel over a period 75 minutes,while the temperature was maintained at 115-125° C. Following a60-minute period of digestion, the reaction mixture was purged withnitrogen, then samples and analyzed. Its Total Amine Value is 120 mgKOH/g, indicating that in this stage, 4.1 moles of ethylene oxide hasbeen consumed for the ethoxylation of 1 mole of coco amine.

Stage 3: Potassium hydroxide (3.7 g, 0.03 moles) was charged to thepressure vessel. The reaction mixture was purged with nitrogen, thenheated at 150° C. for 30 minutes under nitrogen purging to reduce itsmoisture content to less than 0.1%. Ethylene Oxide (330 g, 7.50 moles)was then added to the pressure vessel over a period of 20 minutes whilethe temperature was maintained at 140-150° C. Following a 30-minuteperiod of digestion, the reaction mixture was purge with nitrogen toremove the trace of unreacted ethylene oxide, then cooled to 50° C. anddischarged. Its TAV is 93 mg KOH/g, indicating that total of 9.2 molesof ethylene oxide have been consumed for the ethoxylation each mole ofcoco amine in this preparation. The content of dioxane (about 200 ppm)and EGDs (about 3.0%) of the final product are much lower than thecontent of dioxane (about 12000 ppm) and EGDs (about 11.0%) of itscounterpart made by the acid-catalyzed process.

FIG. 6 illustrates the homologs distribution of the resultingethoxylated product (9NP) and of its counterpart that is prepared by theregular, hydroxide-catalyzed ethoxylation of the coco amine with thesame number of moles (9) of the ethylene oxide (9RP). The degree ofpeaking is 50 for 9NP and 43 for 9RP, indicating that the 9NP productmade by the new process according possesses a peaked ethoxylationdistribution.

Example 7 Effect of Reduction of Higher EO Adduct on the Cloud Point ofGlyphosate Formulations

Adding 0.2% of PEG-600 (˜13.6EO) into a 62% K-glyphosate solutionresulted in a hazy product. However, adding ˜25% diethylene glycol (2EO)into the same K-glyphosate solution resulted in a clear solution. Thisshows that, in concentrated glyphosate solutions, a higher EO adduct hasa much stronger adverse effect on the cloud point than a lower EOadduct. Therefore, even a slight reduction in concentration of thehigher EO adduct could improve the cloud point of glyphosate formulationdramatically. This has been demonstrated in example 3.

Example 8 Homolog Distribution of 9-Mole EO Adduct of TallowaminePrepared by the “R” Ethoxylation Process and the “N” EthoxylationProcess of the Present Invention

Product T/19N was produced using a very similar process as outlined inexample 6. General conditions have been also listed in Table A. Thefinal Total Amine value is 1.50 for T/19N and 1.51 for T/19R.

1. A stable herbicidal formulation which comprises at least one herbicidally active compound and at least one adjuvant surfactant, wherein said surfactant comprises an ethoxylated alkyl(ether)amine with peaked distribution, said ethoxylated alkyl(ether)amine with peaked distribution characterized by a degree of peaking that is at least 5% higher than that of the conventional non-peaked ethoxylated alkyl(ether)amines having the same carbon-chain length and average EO chain length prepared via conventional base catalysis, wherein conventional base catalysis comprises NaOH-catalyzed reaction of RNH₂ with alkylene oxide conducted entirely under autogenous pressure up to 90 psig (621 kPa) at a catalyst concentration of 0.2 wt. % and a temperature between 160° and 180° C.
 2. The formulation of claim 1 wherein said peaked distribution is defined by a degree of peaking at least 7% greater than that of conventional ethoxylated alkyl(ether)amines having the same carbon-chain length and average EO chain length prepared via conventional base catalysis.
 3. The formulation of claim 2 wherein said peaked distribution is defined by a degree of peaking at least 10% greater than that of a conventional ethoxylated alkyl(ether)amines having the same carbon-chain length and average EO chain length prepared via conventional base catalysis.
 4. The formulation of claim 1 wherein said herbicidally active compound is a glyphosate salt.
 5. The formulation of claim 4 characterized by a cloud point at least 3° C. higher than that of substantially similar glyphosate formulations of the same pH containing, as a surfactant component, conventional non-peaked ethoxylated alkyl(ether)amines having the same distribution of carbon-chain length, and average EO chain length prepared via conventional base catalysis.
 6. The formulation of claim 4 wherein the glyphosate salt is selected from the group consisting of Na, K, NH₄, IPA, MEA, DEA, TEA, TMS and mixtures thereof.
 7. The formulation of claim 6 having a cloud point at least 5° C. higher than that of substantially similar glyphosate formulations containing, as a surfactant component, conventional non-peaked ethoxylated alkyl(ether)amines having the same distribution of carbon-chain length, and average EO chain length prepared via conventional base catalysis.
 8. The formulation of claim 6 having a cloud point at least 7° C. higher than that of substantially similar glyphosate formulations containing, as a surfactant component, conventional non-peaked ethoxylated alkyl(ether)amines having the same distribution of carbon-chain length, and average EO chain length prepared via conventional base catalysis.
 9. The formulation of claim 4 wherein the glyphosate formulation is a stable liquid formulation with a concentration of glyphosate in the range of 360-600 g ae/l.
 10. The formulation of claim 4 wherein the ratio of glyphosate (wt % ae) to the peaked distribution ethoxylated alkyl(ether)amine surfactant is between 2:1 and 25:1.
 11. The formulation of claim 1 further comprising a co-herbicide selected from the group consisting essentially of acifluorfen, asulam, benazolin, bentazon, bialaphos, bromacil, bromoxynil, chloramben, clopyralid, 2,4-D, 2,4-DB, pelargonic acid, dalapon, dicamba, dichlorprop, diclofop, endothall, fenac, fenoxaprop, flamprop, fluazifop, fluoroglycofen, fomesafen, fosamine, glufosinate, haloxyfop, imazameth, imazamethabenz, imazamox, imazapyr, imazaquin, imazethapyr, ioxynil, MCPA, MCPB, mecoprop, methylarsonic acid, naptalam, nonanoic acid, picloram, sulfamic acid, 2,3,6-TBA, TCA, triclopyr, salts thereof, and mixtures thereof.
 12. The formulation of claim 1 wherein said at least one ethoxylated alkyl(ether)amine with peaked distribution is of formula (III)

wherein R selected from a linear or branched, saturated or non-saturated alkyl group containing 8-22 carbon atoms, or a group of the formula: R′—O-(A)x-(B)y-(C)z-, wherein A and B are polyalkylene oxide groups, C is methylene group, R′ is a linear or branched, saturated or non-saturated alkyl group containing 8-22 carbon atoms, x, y and z vary from 0 to 5, and n and m varies from 1-15, and each of R² and R³ is independently selected from H, methyl or ethyl, wherein said ethoxylated alkyl(ether)amine with peaked distribution possesses a degree of peaking that is at least 5% higher than that of the conventional non-peaked ethoxylated alkyl(ether)amines having the same carbon-chain length and average EO chain length prepared via conventional base catalysis.
 13. The formulation of claim 12 wherein said alkyl groups are derived from tallow, coconut oil, soybean oil, palm oil, and palm kernel oil.
 14. The formulation of claim 12 wherein the total number of moles (n+m) of the ethylene oxide used for the ethoxylation of the alkyl(ether) amine varies from 3-15.
 15. The formulation of claim 12 wherein ethoxylated alkylamine with peaked distribution is derived from cocoamine, tallowamine, soya amine, oleyl amine, and palm amine.
 16. The formulation of claim 12 wherein said ethoxylated alkyl(ether)amine is selected from the group consisting of an ethoxylated tallowamine with 4 to 15 moles of EO, ethoxylated cocoamine with 4 to 15 moles of EO, ethoxylated alkylamine with 4 to 15 moles of EO and mixtures thereof.
 17. A stable herbicidal formulation which comprises at least one herbicidally active compound and at least one adjuvant surfactant, wherein said adjuvant surfactant comprises an alkoxylated alkyl(ether)amine comprising a mixture of homologs with peaked distribution and corresponding to the formula:

wherein X, Y and Z are alkylene oxide groups containing 2-3 carbon atoms, x is one, each of y, y′, z and z′ is an integer independently varying from 0-20, the sum of (y+y′+z+z′)≧3, each of R² and R³ is independently selected from the group consisting of hydrogen, methyl and ethyl, and R is selected from: (i) a linear or branched, saturated or non-saturated alkyl group containing 12-22 carbon atoms and derived from a primary amine having a molecular weight of at least 200, and (ii) a group of the formula: R¹—O-(A)_(a)-(B)_(b)-(C)_(c)-  Formula III where R¹ is a linear or branched, saturated or non-saturated alkyl group containing 12-22 carbon atoms, each of A and B is an alkylene oxide group, and C is alkylene group containing 2-3 carbon atoms, a and b each varies from 0-5, and c is 1, said adjuvant surfactant being further characterized in that: a first reference aqueous formulation consisting of 540 g/L K-glyphosate a.e., 5.5 wt. % of said adjuvant alkoxylated alkylamine surfactant and 4.5 wt. % bis(2-hydroxyethyl)cocoamine has a cloud point at least 3° C. higher than the cloud point of a second reference aqueous formulation having the same pH as said first reference formulation and consisting of 540 g/L K-glyphosate a.e., 5.5 wt. % of a reference alkoxylated alkyl(ether)amine surfactant and 4.5 wt. % bis(2-hydroxyethyl)cocoamine, said reference surfactant having the same number average value W₀, the same frequency distribution with regard to number of carbon atoms in the substituent R, and the same identity of X, Y and Z as said as adjuvant surfactant, wherein: said reference surfactant is prepared by an NaOH-catalyzed reaction of RNH₂ with alkylene oxide conducted entirely under autogenous pressure up to 90 psig (621 kPa) at a catalyst concentration of 0.2 wt. % and a temperature between 160° and 180° C.; and W₀ is the number average value of (2x+y+y′+z+z′).
 18. A process for preparing alkoxylated alkylamines or alkoxylated alkyl etheramines of formula (I) with peaked distribution, wherein said process comprises reacting a primary alkylamine (II) with an alkylene oxide in the absence of any functional proportion of an alkali catalyst in order to yield the first intermediate (III)

followed by reacting the intermediate (III) with (v) additional moles of alkylene oxide at a temperature between 90° and 130° C. in the absence of any functional proportion of an alkali catalyst to yield product (IV),

wherein R is selected from a linear or branched, saturated or non-saturated alkyl group containing 8-22 carbon atoms, or is a group of the formula: R′—O-(A)_(a)(B)_(b)-(C)_(c)- where R′ is selected from a linear or branched, saturated or non-saturated alkyl group containing 8-22 carbon atoms, A, B, X, Y, Z are alkylene oxide groups containing 2-3 carbon atoms, C is alkylene group containing 2-4 carbon atoms, a, b each vary from 0-5, c is 1, x is 1, each of y, y′, z and z′ is independently selected from 0-15 where the sum of y, y′, z and z′ is at least 1, and v is from 1 to
 7. 19. The process of claim 18 wherein said alkoxylated alkylamine or alkoxylated alkyl ether amine of formula (I) with peaked distribution is characterized by having a degree of peaking at least 5% greater than the distribution of a reference mixture of conventional non-peaked alkoxylated alkylamines having the same carbon chain length and average EO chain length prepared via conventional base catalysis, wherein conventional base catalysis comprises NaOH-catalyzed reaction of RNH₂ with alkylene oxide conducted entirely under autogenous pressure up to 90 psig (621 kPa) at a catalyst concentration of 0.2 wt. % and a temperature between 160° and 180° C.
 20. The process of claim 18 wherein the alkoxylated alkylamine or alkoxylated alkyl ether amine of formula (I) is selected from ethoxylated tallowamine with 4 to 15 EO, ethoxylated soya amine with 4-15EO, ethoxylated coco amine with 4 to 15EO, ethoxylated palm amine with 4-15EO, and mixtures thereof. 